Full Idea
Diogenes replied to one who asserted that there was no such thing as motion by getting up and walking away.
Gist of Idea
When someone denied motion, Diogenes got up and walked away
Source
report of Diogenes (Sin) (reports [c.360 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 06.Di.6
Book Reference
Diogenes Laertius: 'Diogenes Laertius', ed/tr. Yonge,C.D. [Henry G. Bohn 1853], p.231